Chair base



FIG. 1 is a perspective view of a chair base of the invention.

FIG. 2 is a right side view of the chair base of FIG. 1.

FIG. 3 is a top view of the chair base of FIG. 1.

FIG. 4 is a bottom view of the chair base of FIG. 1.

FIG. 5 is a front view of a chair with the chair base of FIG. 1 and a seat shown in broken lines.

FIG. 6 is a right side view of the chair of FIG. 5 with a human person shown sitting in the chair with that person's feet on a ground.

FIG. 7 is a left side view of the chair of FIG. 5.

FIG. 8 is a rear view of the chair of FIG. 5; and,

FIG. 9 is a bottom view of the chair of FIG. 5.

The broken line showing of the chair base is for the purpose of illustrating portions of the article and forms no part of the claim. The broken line showing of a seat, person, and ground are for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for a chair base, as shown and described. 